The invention relates to the general field of monitoring quality of service in a telecommunications network.
It is preferably applied, although this is not limiting on the invention, in heterogeneous networks in which terminals of different types access multimedia services via access networks of different types.
In the current state of the art, the parameters of the quality of service offered to a user are managed by the service provider, the role of the network operator consisting essentially in transporting the multimedia data stream between the service provider and the terminal of the user.
Of course, in this patent application, the expression “service provider” refers to the information technology equipment of the service provider and not the commercial enterprise that offers the service.
FIG. 1 shows this mechanism. This figure shows a terminal 10 in a telecommunications network 1 seeking to download a multimedia stream from a content server 50 of a service provider.
In this example as described here, the terminal 10 accesses the network 1 via a home gateway 11 to which it is connected by a WiFi connection.
The home gateway 11 communicates with routers 13 of the network 1 via a DSLAM 12.
The DSLAM 12 is a known device adapted to recover data streams in transit on telephone lines to which it is connected and to multiplex this data to redirect it to the network of the operator.
It is assumed that on the service provider side the content server 50 is behind a transcoder 52 that adapts the format of the multimedia stream as a function of the characteristics of the terminal 10 and its access network.
In the example described here, the multimedia stream is secured by a firewall 51.
In the current state of the art, the equipment chain shown in FIG. 1 is set up statically by the operator when the user of the terminal 10 subscribes to the service concerned.
For example, if the user subscribes to a video on-demand Internet service, the operator sets up statically a chain in which:                the connection between the home gateway 11 and the DSLAM 12 includes virtual channels VC;        the routers 13 are statically predefined in a routing table of the operator; and        the firewall 51 and the transcoder 52 are chosen to make the multimedia stream secure and to code it as a function of the characteristics of the user terminal (set-top box) 10 and the access network (WiFi, ADSL).        
From the point of view of the operator this configuration is very costly and it is not possible to optimize it as a function of the real demand from users.
Moreover, in practice it obliges the service provider to provide a content dedicated to each type of user equipment and each type of wireless access network (GPRS, UMTS, WiFi, etc.) or cable access network (ADSL, FTTH, etc.).